Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
J Physiol
2003 Jun 15;549Pt 3:683-95. doi: 10.1113/jphysiol.2002.034660.
Show Gene links
Show Anatomy links
C-type inactivation involves a significant decrease in the intracellular aqueous pore volume of Kv1.4 K+ channels expressed in Xenopus oocytes.
Jiang X
,
Bett GC
,
Li X
,
Bondarenko VE
,
Rasmusson RL
.
???displayArticle.abstract???
Channels are water-filled membrane-spanning proteins, which undergo conformational changes as they gate, i.e. open or close. These conformational changes affect both the shape of the channel and the volume of the water-filled pore. We measured the changes in pore volume associated with activation, deactivation, C-type inactivation and recovery in an N-terminal-deleted mutant of the Kv1.4 K+ channel (Kv1.4DeltaN) expressed in Xenopus oocytes. We used giant-patch and cut-open oocyte voltage clamp techniques and applied solutes which are too large to enter the pore mouth to exert osmotic pressure and thus favour smaller pore volume conformations. Applied intracellular osmotic pressure (300 mM sucrose) sped inactivation (time constants (tauinactivation): control, 0.66 +/- 0.09 s; hyperosmotic solution, 0.29 +/- 0.04 s; n = 5, P < 0.01), sped deactivation (taudeactivation: control, 18.8 +/- 0.94 ms; hyperosmotic solution, 8.01 +/- 1.92 ms; n = 5, P < 0.01), and slowed activation (tauactivation: control, 1.04 +/- 0.05 ms; hyperosmotic solution, 1.96 +/- 0.31 ms; n = 5, P < 0.01). These effects were reversible and solute independent. We estimated the pore volume change on inactivation to be about 4500 A3. Osmotic pressure had no effect when applied extracellularly. These data suggest that the intracellular side of the pore closes during C-type inactivation and the volume change is similar to that associated with activation or deactivation. This is also similar to the pore volume estimated from the crystal structure of KcsA and MthK K+ channels. Intracellular osmotic pressure also strongly inhibited re-opening currents associated with recovery from inactivation, which is consistent with a physical similarity between the C-type inactivated and resting closed state.
Almers,
Gating currents and charge movements in excitable membranes.
1978, Pubmed
Almers,
Gating currents and charge movements in excitable membranes.
1978,
Pubmed
Armstrong,
Interaction of tetraethylammonium ion derivatives with the potassium channels of giant axons.
1971,
Pubmed
Balser,
External pore residue mediates slow inactivation in mu 1 rat skeletal muscle sodium channels.
1996,
Pubmed
,
Xenbase
Baukrowitz,
Modulation of K+ current by frequency and external [K+]: a tale of two inactivation mechanisms.
1995,
Pubmed
Baukrowitz,
Use-dependent blockers and exit rate of the last ion from the multi-ion pore of a K+ channel.
1996,
Pubmed
Baukrowitz,
Two functionally distinct subsites for the binding of internal blockers to the pore of voltage-activated K+ channels.
1996,
Pubmed
Bezanilla,
Molecular basis of gating charge immobilization in Shaker potassium channels.
1991,
Pubmed
,
Xenbase
Busch,
Current inactivation involves a histidine residue in the pore of the rat lymphocyte potassium channel RGK5.
1991,
Pubmed
,
Xenbase
Castle,
4-Aminopyridine binding and slow inactivation are mutually exclusive in rat Kv1.1 and Shaker potassium channels.
1994,
Pubmed
,
Xenbase
Choi,
Tetraethylammonium blockade distinguishes two inactivation mechanisms in voltage-activated K+ channels.
1991,
Pubmed
Comer,
Cloning and characterization of an Ito-like potassium channel from ferret ventricle.
1994,
Pubmed
,
Xenbase
De Biasi,
Inactivation determined by a single site in K+ pores.
1993,
Pubmed
Demo,
The inactivation gate of the Shaker K+ channel behaves like an open-channel blocker.
1991,
Pubmed
Doyle,
The structure of the potassium channel: molecular basis of K+ conduction and selectivity.
1998,
Pubmed
Ficker,
Molecular determinants of dofetilide block of HERG K+ channels.
1998,
Pubmed
,
Xenbase
Hilgemann,
Regulation and deregulation of cardiac Na(+)-Ca2+ exchange in giant excised sarcolemmal membrane patches.
1990,
Pubmed
HODGKIN,
A quantitative description of membrane current and its application to conduction and excitation in nerve.
1952,
Pubmed
Hoshi,
Two types of inactivation in Shaker K+ channels: effects of alterations in the carboxy-terminal region.
1991,
Pubmed
,
Xenbase
Hoshi,
Shaker potassium channel gating. I: Transitions near the open state.
1994,
Pubmed
,
Xenbase
Hoshi,
Biophysical and molecular mechanisms of Shaker potassium channel inactivation.
1990,
Pubmed
,
Xenbase
Hummer,
Water conduction through the hydrophobic channel of a carbon nanotube.
2001,
Pubmed
Jiang,
The open pore conformation of potassium channels.
2002,
Pubmed
Kiss,
Contribution of the selectivity filter to inactivation in potassium channels.
1999,
Pubmed
Larsson,
A conserved glutamate is important for slow inactivation in K+ channels.
2000,
Pubmed
,
Xenbase
Li,
Regulation of N- and C-type inactivation of Kv1.4 by pHo and K+: evidence for transmembrane communication.
2003,
Pubmed
,
Xenbase
Lipkind,
A structural motif for the voltage-gated potassium channel pore.
1995,
Pubmed
Liu,
Dynamic rearrangement of the outer mouth of a K+ channel during gating.
1996,
Pubmed
Loots,
Protein rearrangements underlying slow inactivation of the Shaker K+ channel.
1998,
Pubmed
Loots,
Molecular coupling of S4 to a K(+) channel's slow inactivation gate.
2000,
Pubmed
López-Barneo,
Effects of external cations and mutations in the pore region on C-type inactivation of Shaker potassium channels.
1993,
Pubmed
,
Xenbase
Naranjo,
A strongly interacting pair of residues on the contact surface of charybdotoxin and a Shaker K+ channel.
1996,
Pubmed
,
Xenbase
Olcese,
Correlation between charge movement and ionic current during slow inactivation in Shaker K+ channels.
1997,
Pubmed
,
Xenbase
Ortega-Sáenz,
Collapse of conductance is prevented by a glutamate residue conserved in voltage-dependent K(+) channels.
2000,
Pubmed
Perozo,
Structural rearrangements underlying K+-channel activation gating.
1999,
Pubmed
Qu,
Functional roles of the extracellular segments of the sodium channel alpha subunit in voltage-dependent gating and modulation by beta1 subunits.
1999,
Pubmed
,
Xenbase
Rasmusson,
Inactivation of voltage-gated cardiac K+ channels.
1998,
Pubmed
Rasmusson,
C-type inactivation controls recovery in a fast inactivating cardiac K+ channel (Kv1.4) expressed in Xenopus oocytes.
1995,
Pubmed
,
Xenbase
Rayner,
Voltage-sensitive and solvent-sensitive processes in ion channel gating. Kinetic effects of hyperosmolar media on activation and deactivation of sodium channels.
1992,
Pubmed
Ruppersberg,
Cloned neuronal IK(A) channels reopen during recovery from inactivation.
1991,
Pubmed
Starkus,
Ion conduction through C-type inactivated Shaker channels.
1997,
Pubmed
,
Xenbase
Starkus,
Macroscopic Na+ currents in the "Nonconducting" Shaker potassium channel mutant W434F.
1998,
Pubmed
,
Xenbase
Starkus,
Unilateral exposure of Shaker B potassium channels to hyperosmolar solutions.
1995,
Pubmed
,
Xenbase
Todt,
Ultra-slow inactivation in mu1 Na+ channels is produced by a structural rearrangement of the outer vestibule.
1999,
Pubmed
,
Xenbase
Varga,
Cations affect the rate of gating charge recovery in wild-type and W434F Shaker channels through a variety of mechanisms.
2002,
Pubmed
,
Xenbase
Wang,
Modulation of HERG affinity for E-4031 by [K+]o and C-type inactivation.
1997,
Pubmed
,
Xenbase
Wang,
A mutation in segment I-S6 alters slow inactivation of sodium channels.
1997,
Pubmed
Wang,
Kv1.4 channel block by quinidine: evidence for a drug-induced allosteric effect.
2003,
Pubmed
,
Xenbase
Yellen,
Mutations affecting internal TEA blockade identify the probable pore-forming region of a K+ channel.
1991,
Pubmed
Zeuthen,
Mobility of ions, sugar, and water in the cytoplasm of Xenopus oocytes expressing Na(+)-coupled sugar transporters (SGLT1).
2002,
Pubmed
,
Xenbase
Zhang,
Molecular determinants of voltage-dependent inactivation in calcium channels.
1994,
Pubmed
,
Xenbase
Zimmerberg,
Polymer inaccessible volume changes during opening and closing of a voltage-dependent ionic channel.
,
Pubmed
Zimmerberg,
Solute inaccessible aqueous volume changes during opening of the potassium channel of the squid giant axon.
1990,
Pubmed
